If you don’t want to do serious effects, then it’s a better idea to not go to After Effects. But Masking is nog a that serious effect, still you need to go to AE for that because it is not possible (yet) inside Premiere Pro.

A “work-around” to do masking within Premiere Pro could be this:

  1. Put on any video track of your choice the clip that you wish to mask
  2. Now, go to “File” > “New” > “Title”
  3. In the Title creation window, select the Pen Tool
  4. Draw the mask.
  5. Make sure your shape is solid and has got a filled color
  6. Once you close the Title Window your title will appear in the project bin
  7. Drag the on a video track that isĀ aboveĀ the track that you want to mask
  8. And now mask the clip!
  9. Add the Track Matte Key effect to the video clip you want to mask.
    1. Matte: select the video track with the title in it
    2. Composite Using: Matte Alpha
    3. Reverse: Not checked

Add a Gaussian Blur effect to give your mask a little feather. And your mask is done.